ok i understand. hmmmm And what you would say if it would be like this? The Problem is that you can't do a course like on the water at this lake. So we have to race in the other direction. It is not so professional like on the water, but still the same rules

Then red can drop in and block green if there is no zone around the mark within you can not make a tack or gybe (turn) because he has the right of way and green needs to make enough way to not hinder red. Wich means slowing down or make some extra tacks/gybes to avoid red.

All racing tactics you know For green it is best to plan ahead and avoid a situation like this. It all boils down to some simple basic right-of-way rules wich are normally for avoiding a collision but in a race you can use them to your advantage to slow your opponent down if he makes a tactical mistake.

I cannot find anyting about the hull size that apllies to us kiters, if the hull length is just the length of the board the zone is less than 5m. Hard to do any tack within the zone at speeds above 10kn as the tack radius is almost as big as the zone. So not much real world situations happen within the zone at our speeds compared to the slower sailing classes wich tack on their axis.
That leaves mostly only normal rules without the zone for us kiters in real-world racing. But good to know the correct rules, will look into the zone-rules better as i didn't need them until now

Take a look at Appendix F in the RRS link you posted, they have the kite specific rules:
"Zone The area around a mark within a distance of 30 metres. A
kiteboard is in the zone when any part of her hull is in the zone"